package com.iot.common.core.util;

import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import org.springframework.util.Base64Utils;
import org.springframework.util.DigestUtils;

public class AESUtil {

	private static final String KEY_ALGORITHM = "AES";
	private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";// 默认的加密算法

	/**
	 * AES 加密操作
	 *
	 * @param content 待加密内容
	 * @param key     加密密钥
	 * @return 返回Base64转码后的加密数据
	 */
	public static String encrypt(String content, String key) {
		try {
			Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);// 创建密码器

			byte[] byteContent = content.getBytes("utf-8");

			cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(key));// 初始化为加密模式的密码器

			byte[] result = cipher.doFinal(byteContent);// 加密

			return Base64Utils.encodeToString(result);// 通过Base64转码返回

		} catch (Exception ex) {
			Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
		}

		return null;
	}

	/**
	 * AES 解密操作
	 *
	 * @param content
	 * @param key
	 * @return
	 */
	public static String decrypt(String content, String key) {

		try {
			// 实例化
			Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);

			// 使用密钥初始化，设置为解密模式
			cipher.init(Cipher.DECRYPT_MODE, getSecretKey(key));

			// 执行操作
			byte[] result = cipher.doFinal(Base64Utils.decodeFromString(content));
			return new String(result, "utf-8");
		} catch (Exception ex) {
			Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
		}

		return null;
	}

	/**
	 * 生成加密秘钥
	 *
	 * @return
	 */
	private static SecretKeySpec getSecretKey(final String key) {
		// 返回生成指定算法密钥生成器的 KeyGenerator 对象
		KeyGenerator kg = null;

		try {
			kg = KeyGenerator.getInstance(KEY_ALGORITHM);

			// AES 要求密钥长度为 128
			kg.init(128, new SecureRandom(key.getBytes()));

			// 生成一个密钥
			SecretKey secretKey = kg.generateKey();

			return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);// 转换为AES专用密钥
		} catch (NoSuchAlgorithmException ex) {
			Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
		}

		return null;
	}
	
	
	  /**
	  * 随机生成秘钥
	  */
	  public static void getKey() {
	    try {
	      KeyGenerator kg = KeyGenerator.getInstance("AES");
	      kg.init(128);
	      //要生成多少位，只需要修改这里即可128, 192或256
	      SecretKey sk = kg.generateKey();
	      byte[] b = sk.getEncoded();
	      String s = byteToHexString(b);
	      System.out.println(s);
	      System.out.println("十六进制密钥长度为"+s.length());
	      System.out.println("二进制密钥的长度为"+s.length()*4);
	    }
	    catch (NoSuchAlgorithmException e) {
	      e.printStackTrace();
	      System.out.println("没有此算法。");
	    }
	  }
	  /**
	  * 使用指定的字符串生成秘钥
	  */
	  public static void getKeyByPass() {
	    //生成秘钥
	    String password="testkey";
	    try {
	      KeyGenerator kg = KeyGenerator.getInstance("AES");
	      // kg.init(128);//要生成多少位，只需要修改这里即可128, 192或256
	      //SecureRandom是生成安全随机数序列，password.getBytes()是种子，只要种子相同，序列就一样，所以生成的秘钥就一样。
	      kg.init(128, new SecureRandom(password.getBytes()));
	      SecretKey sk = kg.generateKey();
	      byte[] b = sk.getEncoded();
	      String s = byteToHexString(b);
	      System.out.println(s);
	      System.out.println("十六进制密钥长度为"+s.length());
	      System.out.println("二进制密钥的长度为"+s.length()*4);
	    }
	    catch (NoSuchAlgorithmException e) {
	      e.printStackTrace();
	      System.out.println("没有此算法。");
	    }
	  }
	  /**
	  * byte数组转化为16进制字符串
	  * @param bytes
	  * @return
	  */
	  public static String byteToHexString(byte[] bytes) {
	    StringBuffer sb = new StringBuffer();
	    for (int i = 0; i < bytes.length; i++) {
	      String strHex=Integer.toHexString(bytes[i]);
	      if(strHex.length() > 3) {
	        sb.append(strHex.substring(6));
	      } else {
	        if(strHex.length() < 2) {
	          sb.append("0" + strHex);
	        } else {
	          sb.append(strHex);
	        }
	      }
	    }
	    return sb.toString();
	  }
	
	

	public static void main(String[] args) throws NoSuchAlgorithmException {
		String content = "hello,您好";
		String key = "uLsX17jQ7ZOmQslMvN9y0g==";
		System.out.println("content:" + content);
		String s1 = AESUtil.encrypt(content, key);
		System.out.println("s1:" + s1);
		System.out.println("s2:" + AESUtil.decrypt(s1, key));
		
		KeyGenerator keyGenerator = KeyGenerator.getInstance("AES"); 
		keyGenerator.init(128);
		SecretKey secretKey =keyGenerator.generateKey();
		byte[] keyBytes =secretKey.getEncoded();
		 String secretKeyStr =Base64Utils.encodeToString(keyBytes);
		 System.out.println(secretKeyStr);
		//uLsX17jQ7ZOmQslMvN9y0g==
		//k8VjJ8Bn2rLOQK8c
		 
		 getKey();
		 getKeyByPass();
		 
		String ss= DigestUtils.md5DigestAsHex("1234".getBytes());
		System.out.println(ss);

		 

	}

}
